1. Field of the Invention
The present invention generally relates to a shift control device for a vehicle transmission. More specifically, the present invention relates to a shift control device configured to execute a pre-shift operation to control the transmission to achieve a shift waiting state for a next gear range before switching engagement states of clutches of the transmission during shifting.
2. Background Information
Japanese Laid-Open Patent Publication No. 4-282066 discloses a conventional shift control device for controlling a transmission having a first clutch corresponding to one group of gears and a second clutch corresponding to another group of gears. When shifting from one gear to an adjacent gear, the shift control device executes a pre-shift operation in which the next gear is selected from the gear group whose clutch is released (disconnected) and the selected next gear is put into a shift waiting state before switching the engagement states of the first clutch and the second clutch. The pre-shift direction (i.e., upshift or downshift) is determined using a preset pre-shift map and the pre-shift operation is executed to put the selected gear into a waiting state so that the upshift or downshift can be accomplished by switching the engagement states of the first and second clutches.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved shift control device for vehicle transmission. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.